Flow control valve and temperature control device using same

ABSTRACT

Provided is a flow rate control valve capable of suppressing leakage of a fluid when the flow rate control valve completely closes a valve port as compared to a flow rate control valve that does not include a gap reducing portion being provided so as to partially reduce a gap between a valve body and a member opposed to the valve body, and a temperature control device using the flow rate control valve. The flow rate control valve includes: a valve main body including a valve seat, the valve seat having a columnar space and having one or a plurality of valve ports, which allow a fluid to flow therethrough and each have a rectangular cross section; a valve body being provided in a freely rotatable manner in the valve seat of the valve main body so as to open and close the one or the plurality of valve ports, the valve body having a cylindrical shape and having an opening formed in an outer peripheral surface of the valve body; a gap reducing portion being provided so as to partially reduce a gap between the valve body and a member opposed to the valve body; and drive means for driving the valve body to rotate.

TECHNICAL FIELD

The present invention relates to a flow rate control valve and a temperature control device using the same.

BACKGROUND ART

Hitherto, as a technology relating to a flow rate control valve, the applicant of the present invention has already proposed a three-way valve for flow rate control disclosed in, for example, Patent Literature 1.

The three-way valve for flow rate control disclosed in Patent Literature 1 includes: a valve main body including a valve seat, the valve seat having a columnar space and having a first valve port, which allows inflow of a first fluid and has a rectangular cross section, and a second valve port, which allows inflow of a second fluid and has a rectangular cross section; a valve body being provided in a freely rotatable manner in the valve seat of the valve main body so as to simultaneously switch the first valve port from a closed state to an opened state and switch the second valve port from an opened state to a closed state, the valve body having a half-cylindrical shape with a predetermined central angle and having a curved-surface shape at each of both end surfaces of the valve body in a circumferential direction; and drive means for driving the valve body to rotate.

CITATION LIST Patent Literature

[PTL 1] JP 6104443 B2

SUMMARY OF INVENTION Technical Problem

The present invention provides a flow rate control valve capable of suppressing leakage of a fluid when the flow rate control valve completely closes a valve port as compared to a flow rate control valve that does not include a gap reducing portion being provided so as to partially reduce a gap between a valve body and a member opposed to the valve body, and provides a temperature control device using the flow rate control valve.

Solution to Problem

According to the invention of claim 1, provided is a flow rate control valve, including:

a valve main body including a valve seat, the valve seat having a columnar space and having one or a plurality of valve ports, which allow a fluid to flow therethrough and each have a rectangular cross section;

a valve body being provided in a freely rotatable manner in the valve seat of the valve main body so as to open and close the one or the plurality of valve ports, the valve body having a cylindrical shape and having an opening formed in an outer peripheral surface of the valve body;

a gap reducing portion being provided so as to partially reduce a gap between the valve body and a member opposed to the valve body; and

drive means for driving the valve body to rotate.

According to the invention of claim 2, provided is a flow rate control valve, including:

a valve main body including a valve seat, the valve seat having a columnar space and having a first valve port, which allows inflow of a first fluid and has a rectangular cross section, and a second valve port, which allows inflow of a second fluid and has a rectangular cross section;

a valve body being provided in a freely rotatable manner in the valve seat of the valve main body so as to simultaneously switch the first valve port from a closed state to an opened state and switch the second valve port from an opened state to a closed state, the valve body having a half-cylindrical shape with a predetermined central angle and having a curved-surface shape or a flat-surface shape at each of both end surfaces of the valve body in a circumferential direction;

a gap reducing portion being provided so as to partially reduce a gap between the valve body and a member opposed to the valve body; and

drive means for driving the valve body to rotate.

According to the invention of claim 3, provided is a flow rate control valve, including:

a valve main body including a valve seat, the valve seat having a columnar space and having a first valve port, which allows outflow of a fluid and has a rectangular cross section, and a second valve port, which allows outflow of the fluid and has a rectangular cross section;

a valve body being provided in a freely rotatable manner in the valve seat of the valve main body so as to simultaneously switch the first valve port from a closed state to an opened state and switch the second valve port from an opened state to a closed state, the valve body having a half-cylindrical shape with a predetermined central angle and having a curved-surface shape or a flat-surface shape at each of both end surfaces of the valve body in a circumferential direction;

a gap reducing portion being provided so as to partially reduce a gap between the valve body and a member opposed to the valve body; and

drive means for driving the valve body to rotate.

According to the invention of claim 4, provided is a flow rate control valve, including:

a valve main body including a valve seat having a columnar space, the valve main body having a first valve port, which allows a fluid to flow therethrough and has a rectangular cross section, and a third valve port, which allows the fluid to flow therethrough, the first valve port being formed in a peripheral surface of the valve seat, the third valve port being formed in one end portion of the valve seat in an axial direction;

a valve body being provided in a freely rotatable manner in the valve seat of the valve main body, the valve body having a shape corresponding to part of a cylindrical shape with a predetermined central angle, so as to linearly change an opening area of the first valve port;

a gap reducing portion being provided so as to partially reduce a gap between the valve body and a member opposed to the valve body; and

drive means for driving the valve body to rotate.

According to the invention of claim 5, in the flow rate control valve as described in claim 1, the one or the plurality of valve ports are each formed by a valve port forming member, which is a member provided separately from the valve main body, and

in which the gap reducing portion is formed of a distal end portion of the valve port forming member opposed to the valve body.

According to the invention of claim 6, the flow rate control valve as described in claim 5 further includes a gap adjusting member configured to adjust a gap between the valve body and the gap reducing portion.

According to the invention of claim 7, provided is a temperature control device, including:

temperature control means having a flow passage for temperature control, which allows a fluid for temperature control to flow therethrough, the fluid for temperature control including a lower temperature fluid and a higher temperature fluid adjusted in mixture ratio;

first supply means for supplying the lower temperature fluid adjusted to a first predetermined lower temperature;

second supply means for supplying the higher temperature fluid adjusted to a second predetermined higher temperature; and

a flow rate control valve connected to the first supply means and the second supply means, and configured to adjust the mixture ratio between the lower temperature fluid supplied from the first supply means and the higher temperature fluid supplied from the second supply means and allow the fluid for temperature control to flow through the flow passage for temperature control,

in which the flow rate control valve of any one of claims 1, 2, 5, and 6 is used as the flow rate control valve.

According to the invention of claim 8, provided is a temperature control device, including:

temperature control means having a flow passage for temperature control, which allows a fluid for temperature control to flow therethrough, the fluid for temperature control including a lower temperature fluid and a higher temperature fluid adjusted in mixture ratio;

first supply means for supplying the lower temperature fluid adjusted to a first predetermined lower temperature;

second supply means for supplying the higher temperature fluid adjusted to a second predetermined higher temperature;

mixing means, which is connected to the first supply means and the second supply means, for mixing the lower temperature fluid supplied from the first supply means and the higher temperature fluid supplied from the second supply means and supplying a mixture of the lower temperature fluid and the higher temperature fluid to the flow passage for temperature control; and

a flow rate control valve configured to divide the fluid for temperature control having flowed through the flow passage for temperature control between the first supply means and the second supply means while controlling a flow rate of the fluid for temperature control,

in which the flow rate control valve of any one of claims 1, 3, 5, and 6 is used as the flow rate control valve.

Advantageous Effects of Invention

According to the present invention, a flow rate control valve capable of suppressing leakage of a fluid when the flow rate control valve completely closes a valve port as compared to a flow rate control valve that does not include a gap reducing portion being provided so as to partially reduce a gap between a valve body and a member opposed to the valve body, and a temperature control device using the flow rate control valve can be provided.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view for illustrating an outer appearance of a three-way motor valve as one example of a three-way valve for flow rate control according to a first embodiment of the present invention.

FIG. 2 are views including a front view, a right side view thereof, and a bottom view of an actuator, for illustrating the three-way motor valve as one example of the three-way valve for flow rate control according to the first embodiment of the present invention.

FIG. 3 is a sectional view taken along the line A-A of FIG. 2(b), for illustrating the three-way motor valve as one example of the three-way valve for flow rate control according to the first embodiment of the present invention.

FIG. 4 is a sectional perspective view for illustrating relevant parts of the three-way motor valve as one example of the three-way valve for flow rate control according to the first embodiment of the present invention.

FIG. 5 is an exploded perspective view, which is partially in sectional view, for illustrating the relevant parts of the three-way motor valve as one example of the three-way valve for flow rate control according to the first embodiment of the present invention.

FIG. 6 are configuration views for illustrating a valve seat.

FIG. 7 is a horizontal sectional configuration view for illustrating a fitted state of the valve seat.

FIG. 8 is a perspective configuration view for illustrating an adjusting ring.

FIG. 9 are schematic sectional views for illustrating an opened state and a closed state of a valve shaft.

FIG. 10 are configuration views for illustrating the valve shaft.

FIG. 11 are schematic sectional views for illustrating another valve shafts.

FIG. 12 are schematic sectional views for illustrating still another valve shaft.

FIG. 13 is a graph for showing characteristics of the three-way motor valve as one example of the three-way valve for flow rate control according to the first embodiment of the present invention.

FIG. 14 is a graph for showing characteristics of the three-way motor valve as one example of the three-way valve for flow rate control according to the first embodiment of the present invention.

FIG. 15 is a table for showing results of Experiment Example 2.

FIG. 16 is a sectional configuration view for illustrating relevant parts of a three-way motor valve as one example of a three-way valve for flow rate control according to a second embodiment of the present invention.

FIG. 17 is a sectional configuration view for illustrating relevant parts of a three-way motor valve as one example of a three-way valve for flow rate control according to a third embodiment of the present invention.

FIG. 18 is a schematic diagram for illustrating a constant-temperature maintaining device (chiller device) to which the three-way motor valve as one example of the three-way valve for flow rate control according to the first embodiment of the present invention is applied.

FIG. 19 is a schematic diagram for illustrating a constant-temperature maintaining device (chiller device) to which the three-way motor valve as one example of the three-way valve for flow rate control according to the second embodiment of the present invention is applied.

DESCRIPTION OF EMBODIMENTS

In the following, embodiments of the present invention are described with reference to the drawings.

First Embodiment

FIG. 1 is a perspective view for illustrating an outer appearance of a three-way motor valve as one example of a flow rate control valve according to a first embodiment of the present invention. FIG. 2(a) is a front view. FIG. 2(b) is a right side view of FIG. 2(a). FIG. 2(c) is a bottom view of an actuator. FIG. 3 is a sectional view taken along the line A-A of FIG. 2(b). FIG. 4 is a sectional perspective view for illustrating relevant parts of the three-way motor valve. FIG. 5 is an exploded perspective view for illustrating the relevant parts of the three-way motor valve.

A three-way motor valve 1 is constructed as a rotary three-way valve. As illustrated in FIG. 1, the three-way motor valve 1 mainly includes a valve portion 2 arranged at a lower portion thereof, an actuator 3 arranged at an upper portion thereof, and a sealing portion 4 and a coupling portion 5, which are arranged between the valve portion 2 and the actuator 3.

As illustrated in FIG. 2 to FIG. 5, the valve portion 2 includes a valve main body 6 obtained by forming metal, for example, SUS, into a substantially rectangular parallelepiped shape. As illustrated in FIG. 3, a first inflow port 7 and a first valve port 9 are formed in one side surface (left side surface in the illustrated example) of the valve main body 6. The first inflow port 7 allows inflow of a lower temperature fluid as a first fluid. The first valve port 9 has a rectangular cross section, and communicates with a valve seat 8 having a columnar space.

In the first embodiment of the present invention, instead of directly forming the first inflow port 7 and the first valve port 9 in the valve main body 6, the first inflow port 7 and the first valve port 9 are formed in a first valve seat 70 as one example of a valve port forming member, and the first valve seat 70 is fitted to the valve main body 6, thereby providing the first inflow port 7 and the first valve port 9.

As illustrated in FIG. 6, the first valve seat 70 integrally includes a rectangular tube portion 71, a cylindrical portion 72, and a tapered portion 73. The rectangular tube portion 71 has a rectangular tube shape and is provided inside the valve main body 6. The cylindrical portion 72 has a cylindrical shape and is provided outside the valve main body 6. The tapered portion 73 has an outer diameter increasing toward the cylindrical portion 82 side and is arranged between the rectangular tube portion 71 and the cylindrical portion 72. The first valve port 9 is formed in the rectangular tube portion 71 of the first valve seat 70, and has a rectangular prism shape having a rectangular cross section (square cross section in the first embodiment of the present invention). Further, the first inflow port 7 is formed in the cylindrical portion 72 of the first valve seat 70, and has a columnar shape having a circular cross section substantially circumscribing the first valve port 9.

As a material for the first valve seat 70, for example, so-called “super engineering plastic” is used. The super engineering plastic has higher heat resistance and higher mechanical strength under a high temperature than ordinary engineering plastic. Examples of the super engineering plastic include, for example, polyether ether ketone (PEET), polyphenylene sulfide (PPS), polyether sulfone (PES), polyamide imide (PAI), a liquid crystal polymer (LCP), polytetrafluoroethylene (PTFE), polychlorotrifluoroethylene (PCTFE), polyvinylidene fluoride (PVDF), or composite materials thereof. As the material for the first valve sheet 70, there may be used, for example, “TECAPEEK” (trademark) manufactured by Ensinger Japan Co., Ltd. serving as a PEEK resin material for cutting work, and “TECAPEEK TF 10 blue” (product name) having blending therein 10% PTFE, which is excellent in sliding property, is particularly suitably used.

As illustrated in FIG. 4 and FIG. 5, a recess 76 is formed in the valve main body 6 by, for example, machining. The recess 76 has a shape corresponding to an outer shape of the first valve seat 70 and similar to the shape of the valve seat 70. The recess 76 includes a rectangular tube portion 76 a corresponding to the rectangular tube portion 71 of the first valve seat 70, a cylindrical portion 76 b corresponding to the cylindrical portion 72, and a tapered portion 76 c corresponding to the tapered portion 73. The first valve seat 70 is fitted in the recess 76 of the valve main body 6 in a liquid-tight manner. Further, as illustrated in FIG. 3 and FIG. 4, a slight gap is defined between the tapered portion 73 of the first valve seat 70 and the tapered portion 76 c of the recess 76. As a result, under a state in which the first valve seat 70 is fitted in the recess 76 of the valve main body 6, by a distance corresponding to the slight gap between the tapered portion 73 and the tapered portion 76 c of the recess 76, the valve seat 70 is freely movable by a length of from about several hundred micrometers to about several millimeters along inward and outward directions of the valve main body 6, and the fitting position of the valve seat 70 is adjustable.

As illustrated in FIG. 6(b), a concave portion 74 is formed at a distal end of the rectangular tube portion 71 of the first valve seat 70. The concave portion 74 is one example of a gap reducing portion having an arc shape in plan view, which forms part of a curved surface of a columnar shape corresponding to the valve seat 8 having a columnar shape in the valve main body 6. A curvature radius R of the concave portion 74 is set to a value substantially equal to a curvature radius of the valve seat 8 or a curvature radius of a valve shaft 34. In order to prevent biting of the valve shaft 34 to be rotated inside the valve seat 8, as described later, the valve seat 8 of the valve main body 6 defines a slight gap with respect to an outer peripheral surface of the valve shaft 34. As illustrated in FIG. 7, the concave portion 74 of the first valve seat 70 is fitted so as to protrude toward the valve shaft 34 side more than the valve seat 8 of the valve main body 6 under a state in which the first valve seat 70 is fitted to the valve main body 6. As a result, a gap G between the valve shaft 34 and an inner surface of the valve seat 8 of the valve main body 6 being a member opposed to the valve shaft 34 is partially set to a value reduced by the protruding amount of the concave portion 74 of the first valve seat 70 as compared to that of a gap between the valve shaft 34 and another portion of the valve seat 8. Thus, a gap G1 between the concave portion 74 of the first valve seat 70 and the valve shaft 34 is set to a desired value (G1<G2) smaller than (or a gap narrower than) a gap G2 between the valve shaft 34 and the inner surface of the valve seat 8. The gap G1 between the concave portion 74 of the first valve seat 70 and the valve shaft 34 may correspond to a state in which the concave portion 74 of the valve seat 70 is held in contact with the valve shaft 34, that is, a state in which no gap is defined (the gap G1=0).

However, in a case in which the concave portion 74 of the first valve seat 70 is held in contact with the valve shaft 34, there is a fear in that rotational torque of the valve shaft 34 is increased due to contact resistance of the concave portion 74 when the valve shaft 34 is driven to rotate. Accordingly, a contact degree of the concave portion 74 of the first valve seat 70 with the valve shaft 34 is adjusted in consideration of the rotational torque of the valve shaft 34. That is, the contact degree is adjusted to such an extent as to involve no increase in the rotational torque of the valve shaft 34 or involve slight increase even when the rotational torque is increased, and cause no trouble for rotation of the valve shaft 34.

As illustrated in FIG. 6, an annular portion 75 is formed on an outer end surface of the cylindrical portion 72 of the first valve seat 70. The annular portion 75 has an outer diameter smaller than that of the cylindrical portion 72, and has a cylindrical shape having a small thickness and a short length. An O-ring 15 is externally fitted to the annular portion 75 of the first valve seat 70. The O-ring 15 is made of a synthetic resin having heat resistance, and has an annular shape having a circular or rectangular cross section. An O-ring retainer 16 is fitted to an outer side of the O-ring 15. The O-ring retainer 16 is made of a synthetic resin having heat resistance or metal, and has an annular shape having a rectangular cross section. Moreover, an adjusting ring 77 is arranged on an outer side of the first valve seat 70. The adjusting ring 77 is one example of a gap adjusting member configured to adjust the gap G1 between the valve shaft 34 and the concave portion 74 of the first valve seat 70. As illustrated in FIG. 8, the adjusting ring 77 is made of a synthetic resin having heat resistance or metal, and is formed of a cylindrical member having a relatively small length and a male thread 77 a formed in an outer peripheral surface thereof. Recessed grooves 77 b are formed in an outer end surface of the adjusting ring 77 so as to be 180 degrees opposed to each other. When the adjusting ring 77 is fastened and fitted into a female thread portion 78 formed in the valve main body 6, a jig (not shown) for adjusting a fastening amount is locked to the recessed grooves 77 b so as to turn the adjusting ring 77.

The female thread portion 78 for fitting the adjusting ring 77 is formed in the valve main body 6. A tapered portion 79 is formed at an opening end portion located on an outer side of the female thread portion 78, and has a diameter increasing toward an outer periphery thereof. An O-ring 79 a is interposed in the tapered portion 79.

The adjusting ring 77 is configured to adjust an amount (distance) of pushing and moving the first valve seat 70 inward by the adjusting ring 77 through adjustment of a fastening amount of the adjusting ring 77 with respect to the female thread portion 78 of the valve main body 6. When the fastening amount of the adjusting ring 77 is increased, as illustrated in FIG. 7, the first valve seat 70 is pushed by the adjusting ring 77 through intermediation of the O-ring retainer 16 so that the concave portion 74 protrudes from an inner peripheral surface of the valve seat 8 and is displaced in a direction of approaching the valve shaft 34. Thus, the gap G1 between the concave portion 74 and the valve shaft 34 is reduced. Further, when the fastening amount of the adjusting ring 77 is set to a small amount in advance, the distance of pushing and moving the first valve seat 70 by the adjusting ring 77 is reduced. As a result, the first valve seat 70 is arranged apart from the valve shaft 34, and the gap G1 between the concave portion 74 of the first valve seat 70 and the valve shaft 34 is relatively increased. The male thread 77 a of the adjusting ring 77 and the female thread portion 78 of the valve main body 6 are each set to have a small pitch. With this configuration, a protruding amount of the first valve seat 70 can be finely adjusted.

Further, as illustrated in FIG. 3 and FIG. 4, a first flange member 10, which is configured to connect a pipe (not shown) allowing inflow of the lower temperature fluid, is mounted to one side surface of the valve main body 6 with four hexagon socket head cap screws 11 (see FIG. 3). In FIG. 5, a reference symbol 11 a denotes a screw hole in which the hexagon socket head cap screw 11 is fastened. Similarly to the valve main body 6, the first flange member 10 is made of metal, for example, SUS. The first flange member 10 includes a flange portion 12, an insertion portion 13, and a pipe connecting portion 14. The flange portion 12 has a side surface having the same rectangular shape as the side surface of the valve main body 6. The insertion portion 13 has a cylindrical shape and protrudes from an inner surface of the flange portion 12 (see FIG. 4). The pipe connecting portion 14 has a substantially cylindrical shape having a large thickness and protrudes from an outer surface of the flange portion 12. A pipe (not shown) is connected to the pipe connecting portion 14. An inner periphery of the pipe connecting portion 14 is set to, for example, Rc ½ being a standard for a tapered female thread having a bore diameter of about 21 mm, or a female thread having a diameter of about 0.58 inches. The shape of the pipe connecting portion 14 is not limited to the tapered female thread or the female thread. The pipe connecting portion 14 may have, for example, a tube fitting shape that allows a tube to be fitted thereto. The pipe connecting portion 14 may have any shape as long as the pipe connecting portion 14 enables inflow of a fluid through the first inflow port 7.

A second inflow port 17 and a second valve port 18 are formed in another side surface (right side surface in FIG. 3) of the valve main body 6. The second inflow port 17 allows inflow of a higher temperature fluid as a second fluid. The second valve port 18 has a rectangular cross section, and communicates with the valve seat 8 having the columnar space.

In the first embodiment of the present invention, instead of directly forming the second inflow port 17 and the second valve port 18 in the valve main body 6, the second inflow port 17 and the second valve port 18 are formed in a second valve seat 80 as one example of the valve port forming member, and the second valve seat 80 is fitted to the valve main body 6, thereby providing the second inflow port 17 and the second valve port 18.

The second valve seat 80 has a configuration similar to the configuration of the first valve seat 70 as illustrated in FIG. 6 with the reference symbol of the second valve seat 80 put in parentheses. That is, the second valve seat 80 integrally includes a rectangular tube portion 81, a cylindrical portion 82, and a tapered portion 83. The rectangular tube portion 81 has a rectangular tube shape and is provided inside the valve main body 6. The cylindrical portion 82 has a cylindrical shape and is provided outside the valve main body 6. The tapered portion 83 has an outer diameter increasing toward the cylindrical portion 82 side and is arranged between the rectangular tube portion 81 and the cylindrical portion 82. The second valve port 18 is formed in the rectangular tube portion 81 of the second valve seat 80, and has a rectangular prism shape having a rectangular cross section (square cross section in the first embodiment of the present invention). Further, the second inflow port 17 is formed in the cylindrical portion 82 of the second valve seat 80, and has a cylindrical shape having a circular cross section substantially circumscribing the second valve port 18.

As illustrated in FIG. 4 and FIG. 5, a recess 86 is formed in the valve main body 6 by, for example, machining. The recess 86 has a shape corresponding to an outer shape of the second valve seat 80 and similar to the shape of the valve seat 80. The recess 86 includes a rectangular tube portion 86 a corresponding to the rectangular tube portion 81 of the second valve seat 80, a cylindrical portion 86 b corresponding to the cylindrical portion 82, and a tapered portion 86 c corresponding to the tapered portion 83. The second valve seat 80 is fitted in the recess 86 of the valve main body 6 in a liquid-tight manner. Further, as illustrated in FIG. 3 and FIG. 4, a slight gap is defined between the tapered portion 83 of the second valve seat 80 and the tapered portion 86 c of the recess 86. As a result, under a state in which the second valve seat 80 is fitted in the recess 86 of the valve main body 6, by a distance corresponding to the slight gap between the tapered portion 83 and the tapered portion 86 c of the recess 86, the valve seat 80 is freely movable by a length of from about several hundred micrometers to about several millimeters along inward and outward directions of the valve main body 6, and the fitting position of the valve seat 80 is adjustable. The second valve seat 80 is made of the same material as that for the first valve seat 70.

As illustrated in FIG. 6, an annular portion 85 is formed on an outer end surface of the cylindrical portion 82 of the second valve seat 80. The annular portion 85 has an outer diameter smaller than that of the cylindrical portion 82, and has a cylindrical shape having a short length and a small thickness. An O-ring 24 is externally fitted to the annular portion 85 of the second valve seat 80. Further, an O-ring retainer 25 is fitted to an outer side of the O-ring 24. Moreover, an adjusting ring 87 is arranged on an outer side of the second valve seat 80. The adjusting ring 87 is one example of a gap adjusting member configured to adjust a gap G3 between the valve shaft 34 and a distal end portion 84 of the second valve seat 80. The value of the gap G3 is set to be the same as the gap G1. As illustrated in FIG. 8 with the reference symbol of the adjusting ring 87 put in parentheses, the adjusting ring 87 is formed of a cylindrical member having a relatively small length and a male thread 87 a formed in an outer peripheral surface thereof. Recessed grooves 87 b are formed in an outer end surface of the adjusting ring 87 so as to be 180 degrees opposed to each other. When the adjusting ring 87 is fastened and fitted into a female thread portion 88 formed in the valve main body 6, a jig (not shown) for adjusting a fastening amount is locked to the recessed grooves 87 b so as to turn the adjusting ring 87.

The female thread portion 88 for fitting the adjusting ring 87 is formed in the valve main body 6. A tapered portion 89 is formed at an opening end portion located on an outer side of the female thread portion 88, and has a diameter increasing toward an outer periphery thereof. An O-ring 89 a is interposed in the tapered portion 89.

As illustrated in FIG. 3 and FIG. 4, a second flange member 19 for connecting a pipe (not shown) which allows inflow of the higher temperature fluid is mounted to the another side surface of the valve main body 6 with four hexagon socket head cap screws 20 (see FIG. 3). Similarly to the first flange member 10, the second flange member 19 is made of metal, for example, SUS. The second flange member 19 has a flange portion 21, an insertion portion 22, and a pipe connecting portion 23. The flange portion 21 has a side surface having the same rectangular shape as the side surface of the valve main body 6. The insertion portion 22 has a cylindrical shape and protrudes from an inner surface of the flange portion 21. The pipe connecting portion 23 has a substantially cylindrical shape having a large thickness and protrudes from an outer surface of the flange portion 21. A pipe (not shown) is connected to the pipe connecting portion 23. An inner periphery of the pipe connecting portion 23 is set to, for example, Rc ½ being a standard for a tapered female thread having a bore diameter of about 21 mm, or a female thread having a diameter of about 0.58 inches. Similarly to the pipe connecting portion 14, the shape of the pipe connecting portion 23 is not limited to the tapered female thread or the female thread. The pipe connecting portion 23 may have, for example, a tube fitting shape that allows a tube to be fitted thereto. The pipe connecting portion 23 may have any shape as long as the pipe connecting portion 23 enables inflow of a fluid through the second inflow port 17.

Here, the lower temperature fluid as the first fluid and the higher temperature fluid as the second fluid are fluids to be used for temperature control. A fluid having a relatively lower temperature is referred to as “lower temperature fluid,” and a fluid having a relatively higher temperature is referred to as “higher temperature fluid.” Thus, the lower temperature fluid and the higher temperature fluid have a relative relationship. The lower temperature fluid is not a fluid having an absolutely low temperature, and the higher temperature fluid is not a fluid having an absolutely high temperature. As the lower temperature fluid and the higher temperature fluid, for example, under air pressure of from 0 MPa to 1 MPa and within a temperature range of from about 0° C. to about 80° C., water (such as pure water) adjusted to a temperature of from about 0° C. to about 30° C. and water (pure water) adjusted to a temperature of from about 50° C. to about 80° C. are suitably used, respectively. Further, as the lower temperature fluid and the higher temperature fluid, for example, within a temperature range of from about −20° C. to about +120° C., there is used a fluid such a fluorine-based inert liquid, for example, Fluorinert (trademark) and ethylene glycol, which are neither frozen at a temperature of about −20° C. nor boiled at a temperature of about +120° C.

Further, as illustrated in FIG. 3, in a lower end surface of the valve main body 6, an outflow port 26 having a circular cross section as the third valve port is opened. The outflow port 26 allows outflow of a fluid for temperature control, which is a mixture of the lower temperature fluid and the higher temperature fluid. A third flange member 27 for connecting a pipe (not shown) which allows outflow of the fluid for temperature control is mounted to the lower end surface of the valve main body 6 with four hexagon socket head cap screws 28. A cylindrical portion 26 b is opened in a lower end portion of the outflow port 26 through a tapered portion 26 a. The tapered portion 26 a is tapered and increased in diameter so as to allow the third flange member 27 to be fitted thereto. Similarly to the first and second flange members 10 and 19, the third flange member 27 is made of metal, for example, SUS. The third flange member 27 has a flange portion 29, an insertion portion 30, and a pipe connecting portion 31. The flange portion 29 has a planar surface having a rectangular shape, which is smaller than the lower end surface of the valve main body 6. The insertion portion 30 has a cylindrical shape and protrudes from an upper end surface of the flange portion 29. The pipe connecting portion 31 has a substantially cylindrical shape having a large thickness and protrudes from a lower end surface of the flange portion 29. A pipe (not shown) is connected to the pipe connecting portion 31. An inner periphery of the pipe connecting portion 31 is set to, for example, Rc ½ being a standard for a tapered female thread having a bore diameter of about 21 mm and a female thread having a diameter of about 0.58 inches. An inner peripheral end on a lower end of the third inflow port 26 of the valve main body 6 has a chamfer 33 to allow an O-ring 32 to be mounted between the third outflow port 26 of the valve main body 6 and the flange portion 29 of the third flange member 27. The shape of the pipe connecting portion 31 is not limited to the tapered female thread or the female thread. The pipe connecting portion 31 may have, for example, a tube fitting shape that allows a tube to be fitted thereto. The pipe connecting portion 31 may have any shape as long as the pipe connecting portion 31 enables outflow of a fluid through the outflow port 26.

The valve seat 8 is formed in a center of the valve main body 6. The valve seat 8 forms the first valve port 9 having a rectangular cross section and the second valve port 18 having a rectangular cross section when the first valve seat 70 and the second valve seat 80 are fitted to the valve main body 6. The valve seat 8 has a space having a columnar shape corresponding to an outer shape of a valve body to be described later. Further, part of the valve seat 8 is formed by the first valve seat 70 and the second valve seat 80. The valve seat 8 having a columnar shape is provided in a state of penetrating an upper end surface of the valve main body 6. As illustrated in FIG. 9, the first valve port 9 and the second valve port 18 provided to the valve main body 6 are arranged in an axial symmetrical manner with respect to a center axis (rotation axis) C of the valve seat 8 having a columnar shape. More specifically, the first valve port 9 and the second valve port 18 are arranged so as to be orthogonal to the valve seat 8 having a columnar shape. One end edge of the first valve port 9 is opened in a position opposed to another end edge of the second valve port 18 through the center axis C, that is, in a position different by 180°. Further, another end edge of the first valve port 9 is opened in a position opposed to one end edge of the second valve port 18 through the center axis C, that is, in a position different by 180°. In FIG. 9, for convenience, illustration of a gap between the valve seat 8 and the valve shaft 34 is omitted.

Further, as illustrated in FIG. 3 and FIG. 4, the first valve port 9 and the second valve port 18 are openings each having a rectangular cross section such as a square cross section and are formed through fitting through fitting of the first valve seat 70 and the second valve seat 80 to the valve main body 6 as described above. A length of one side of the first valve port 9 and the second valve port 18 is set to be smaller than a diameter of the first inflow port 7 and the second inflow port 17. The first valve port 9 and the second valve port 18 have a cross section having a rectangular shape inscribed in the first inflow port 7 and the second inflow port 17.

As illustrated in FIG. 10, a valve shaft 34 as one example of the valve body has an outer shape obtained by forming metal, for example, SUS, into a substantially columnar shape. The valve shaft 34 mainly includes a valve body portion 35, upper and lower shaft support parts 36 and 37, a sealing portion 38, and a coupling par 40, which are integrally provided. The valve body portion 35 functions as a valve body. The upper and lower shaft support parts 36 and 37 are provided above and below the valve body portion 35, respectively, and support the valve shaft 34 in a freely rotatable manner. The sealing portion 38 is provided to an upper portion of the upper shaft support portion 36. The coupling portion 40 is provided to an upper portion of the sealing portion 38 through intermediation of a tapered portion 39.

The upper and lower shaft support parts 36 and 37 each have a cylindrical shape having an outer diameter smaller than that of the valve body portion 35 and having an equal diameter. A length of the lower shaft support portion 37 in an axial direction is set to be slightly larger than that of the upper shaft support portion 36. As illustrated in FIG. 3, the lower shaft support portion 37 is supported in a freely rotatable manner through intermediation of a bearing 41 by a lower end of the valve seat 8 provided to the valve main body 6. An annular support portion 42 supporting the bearing 41 is provided at a lower portion of the valve seat 8 so as to protrude toward an inner periphery. The bearing 41, the support portion 42, and the insertion portion 30 of the third flange member 27 are set to have an equal inner diameter, and are configured to allow outflow of the fluid for temperature control, which has passed through an inside of the valve body portion 35, to the connecting portion 31 of the third flange member 27 with little resistance. Meanwhile, a thrust washer 43 is mounted to the upper shaft support portion 36 to reduce a load generated by the valve shaft 34 pressed by a sealing case 53 to be described later.

Further, as illustrated in FIG. 3 and FIG. 10 (b), the valve body portion 35 has a cylindrical shape having an opening formed therein. The opening 44 has a substantially half-cylindrical shape with an opening height H2, which is smaller than an opening height H1 of the first and second valve ports 9 and 18. A valve operating portion 45 having the opening 44 of the valve body portion 35 has a half-cylindrical shape (substantially half-cylindrical shape of a cylindrical portion excluding the opening 44) with a predetermined central angle α (for example, about) 190°. The valve operating portion 45 is arranged in a freely rotatable manner in the valve seat 8 and held in non-contact with an inner peripheral surface of the valve seat 8 through a slight gap to prevent metal-to-metal biting. Accordingly, with the valve body portion 35 positioned above and below the opening 44 included, the valve operating portion 45 simultaneously switches the first valve port 9 from a closed state to an opened state and the second valve port 18 from an opened state to a closed state in a reverse direction. As illustrated in FIG. 9, upper and lower valve shaft parts 46 and 47 arranged above and below the valve operating portion 45 each have a cylindrical shape having an outer diameter equal to that of the valve operating portion 45, and are held in non-contact with the inner peripheral surface of the valve seat 8 in a freely rotatable manner through a slight gap. In an inside over the valve operating portion 45, the upper and lower valve shaft parts 46 and 47, and the sealing portion 38, a space 48 is provided in a state of penetrating the valve shaft 34 toward a lower edge thereof. The space 48 has a columnar shape having a diameter reduced in size toward an upper end thereof.

Further, a cross section of each of both end surfaces 45 a and 45 b of the valve operating portion 45 in a circumferential direction (rotation direction), which is taken along a direction intersecting (orthogonal to) the center axis C, has a curved-surface shape. More specifically, as illustrated in FIG. 11 (a), the cross section of each of the both end portions 45 a and 45 b of the valve operating portion 45 in the circumferential direction, which is taken along a direction intersecting the rotation axis C, has an arc shape being convex toward the opening 44. A curvature radius of each of the both end portions 45 a and 45 b is set to, for example, a half of a thickness T of the valve operating portion 45. As a result, a cross section of each of the both end portions 45 a and 45 b is a semicircular shape.

The cross section of each of the both end portions 45 a and 45 b of the valve operating portion 45 in the circumferential direction, which is taken along a direction intersecting the rotation axis C, is not limited to an arc shape. It is only necessary that each of the both end surfaces 45 a and 45 b in the circumferential direction (rotation direction) have a curved-surface shape. As illustrated in FIG. 11(b), the cross section of each of the both end portions 45 a and 45 b of the valve operating portion 45 in the circumferential direction, which is taken along a direction intersecting the rotation axis C, may have a curved shape obtained by smoothly connecting a first curved portion 50, which is positioned on an outer peripheral side, and a second curved portion 51, which is positioned on an inner peripheral side and has a curvature radius smaller than that of the first curved portion 50.

As illustrated in FIG. 11, when the valve shaft 34 is driven to rotate to open and close the first and second valve ports 9 and 18, in flows of the lower temperature fluid and the higher temperature fluid, the both end portions 45 a and 45 b of the valve operating part 45 in the circumferential direction are moved (rotated) so as to protrude from or retreat to the ends of the first and second valve ports 9 and 18 in the circumferential direction. Accordingly, the first and second valve ports 9 and 18 are switched from the opened state to the closed state, or from the closed state to the opened state. At this moment, each of the both end portions 45 a and 45 b of the valve operating portion 45 in the circumferential direction have a cross section having a curved-surface shape so as to further linearly change opening areas of the first and second valve ports 9 and 18 with respect to a rotation angle of the valve shaft 34.

Further, as illustrated in FIG. 12, the both end portions 45 a and 45 b of the valve operating portion 45 in the circumferential direction may each have a flat shape in a radial direction of the valve operating portion 45.

As illustrated in FIG. 11 (b), in a case where the cross section of each of the both end portions 45 a and 45 b of the valve operating portion 45 in the circumferential direction has a curved-surface shape, even when the opening degree of the valve shaft 34 exceeds 50%, the opening areas of the first and second valve ports 9 and 18 with respect to the rotation angle of the valve shaft 34 can be further linearly changed.

As illustrated in FIG. 3, the sealing portion 4 is configured to seal the valve shaft 34 in a liquid-tight state. The sealing portion 4 has the sealing case 53 obtained by forming metal, for example, SUS, into a cylindrical shape. The sealing case 53 has an insertion through hole 52 through which the valve shaft 34 is inserted. The sealing case 53 is arranged in a recessed portion 54 that is formed in an upper end surface of the valve main body 6 and has a columnar shape. The sealing case 53 has such structure that a positional relationship between the sealing case 53 and the valve shaft 34 is determined through annular sealing members 55 and 56 and that the sealing case 53 is fixed through a positioning pin (not shown) so as to be prevented from rotating with respect to a spacer member 59 to be described later. On an inner peripheral surface of the sealing case 53, the two annular sealing members 55 and 56 formed of, for example, O-rings for sealing the valve shaft 34 are arranged in a vertical direction. As the sealing members 55 and 56, for example, an O-ring made of ethylene-propylene rubber (EPDM) is used. The upper sealing member 56 is retained by a retaining member 56 a. Further, the annular sealing member 57 formed of, for example, an O-ring seals the sealing case 53 with respect to the valve main body 6.

The coupling portion 5 is arranged between the valve main body 6, in which the sealing portion 4 is provided, and the actuator 3. The coupling portion 5 is configured to connect the valve shaft 34 and a rotation shaft (not shown), which allows the valve shaft 34 to be integrally rotated, to each other. The coupling portion 5 includes a spacer member 59, an adaptor plate 60, and a coupling member 62. The spacer member 59 is arranged between the sealing portion 4 and the actuator 3. The adaptor plate 60 is fixed to an upper portion of the spacer member 59. The coupling member 62 is accommodated in a space 61 having a columnar shape formed in a state of penetrating an inside of the spacer member 59 and the adaptor plate 60, and connects the valve shaft 34 and the rotation shaft (not shown) to each other. The spacer member 59 is obtained by forming metal, for example, SUS, into a parallelepiped shape, which has substantially the same planar shape as that of the valve main body 6 and a relatively small height. The spacer member 59 is fixed to both the valve main body 6 and the adaptor plate 60 through means such as screw fastening. Further, as illustrated in FIG. 2(c), the adaptor plate 60 is obtained by forming metal, for example, SUS, into a plate-like shape having a planar polygonal shape. The adaptor plate 60 is mounted to the base 64 of the actuator 3 in a fixed state with hexagon socket head cap screws 63.

As illustrated in FIG. 3, the coupling member 62 is obtained by forming, for example, metal, a synthetic resin having heat resistance, or ceramics into a columnar shape. A recessed groove 65 is formed so as to penetrate an upper end of the valve shaft 34 in a horizontal direction. The valve shaft 34 is coupled and fixed to the coupling member 62 by fitting a projecting portion 66 of the coupling member 62 into the recessed groove 65. Meanwhile, a recessed groove 67 is formed in an upper end of the coupling member 62 so as to penetrate the coupling member 62 in a horizontal direction. The rotation shaft (not shown) is coupled and fixed to the coupling member 62 by fitting a projecting portion (not shown) into the recessed groove 67 of the coupling member 62. The spacer member 59 has an opening 68 formed in a side surface thereof for detecting leakage of a liquid through the insertion through hole 52 when the liquid leaks from the sealing members 55 and 56. The opening 68 is set to, for example, Rc 1/16 being a standard for a tapered female thread having a bore diameter of about 8 mm.

As illustrated in FIG. 2, the actuator 3 includes the base 64 having a planar surface having a rectangular shape. A casing 90 is mounted to an upper portion of the base 64 with screws 91. The casing 90 is constructed as a box body having a rectangular parallelepiped shape, which contains drive means including a stepping motor, an encoder, and the like. The drive means in the actuator 3 only needs to be capable of rotating the rotation shaft 58 in a desired direction with predetermined accuracy based on control signals, and configuration thereof is not limited. The drive means includes a stepping motor, a driving force transmission mechanism, and an angle sensor. The driving force transmission mechanism is configured to transmit a rotational driving force of the stepping motor to the rotation shaft 58 through intermediation of driving force transmission means, for example, a gear. The angle sensor is, for example, an encoder or the like configured to detect a rotation angle of the rotation shaft 58.

In FIG. 2, a reference symbol 92 denotes a stepping motor-side cable, and a reference symbol 93 denotes an angle sensor-side cable. The stepping motor-side cable 92 and the angle sensor-side cable 93 are connected to a control device (not shown) configured to control the three-way motor valve 1.

<Operation of Three-way Motor Valve>

In the three-way motor valve 1 according to the embodiment of the present invention, the flow rate of the lower temperature fluid and the higher temperature fluid is controlled as follows.

As illustrated in FIG. 5, at the time of assembly or adjustment for use, in the three-way motor valve 1, the first flange member 10 and the second flange member 19 are removed from the valve main body 6 so that the adjusting rings 77 and 87 are exposed to the outside. Under this state, when the fastening amounts of the adjusting rings 77 and 87 with respect to the valve main body 6 are adjusted through use of the jig (not shown), as illustrated in FIG. 7, the protruding amounts of the first valve seat 70 and the second valve seat 80 from the valve seat 8 of the valve main body 6 are changed. When the fastening amount of the adjusting ring with respect to the valve main body 6 is increased, the concave portion of the first valve seat 70 or the concave portion of the second valve seat 80 protrudes from the inner peripheral surface of the valve seat 8 of the valve main body 6 so that the gap G1 between the outer peripheral surface of the valve shaft 34 and the concave portion of the first valve seat 70 or the concave portion of the second valve seat 80 is reduced. Meanwhile, when the fastening amount of the adjusting ring with respect to the valve main body 6 is reduced, a protruding length of the concave portion of the first valve seat 70 or the concave portion of the second valve seat 80 from the inner peripheral surface of the valve seat 8 of the valve main body 6 is reduced so that the gap G1 between the outer peripheral surface of the valve shaft 34 and the concave portion of the first valve seat 70 or the concave portion of the second valve seat 80 is increased.

In the first embodiment of the present invention, the gap G1 between the outer peripheral surface of the valve shaft 34 and the concave portion of the first valve seat 70 or the concave portion of the second valve seat 80 is set to from about 5 μm to about 10 μm. However, the gap G1 between the outer peripheral surface of the valve shaft 34 and the concave portion of the first valve seat 70 or the concave portion of the second valve seat 80 is not limited to the above-mentioned value. The gap G1 may be set to a value smaller than the above-mentioned value, for example, may satisfy the gap G1=0 μm. Alternatively, the gap G1 may be set to 10 μm or more.

As illustrated in FIG. 1, through the first flange member 10 and the second flange member 19, the lower temperature fluid adjusted to a predetermined lower temperature and the higher temperature fluid adjusted to a predetermined higher temperature are supplied through pipes (not shown) to the three-way motor valve 1. As illustrated in FIG. 9(a), for example, in an initial state before start of operation, the three-way motor valve 1 is brought into a state in which the valve operating portion 45 of the valve shaft 34 simultaneously closes (completely closes) the first valve port 9 and opens (completely opens) the second valve port 18.

As illustrated in FIG. 3, in the three-way motor valve 1, when the stepping motor (not shown) provided in the actuator 3 is driven to rotate by a predetermined amount, the rotation shaft 58 is driven to rotate in accordance with a rotation amount of the stepping motor. In the three-way motor valve 1, when the rotation shaft 58 is driven to rotate, the valve shaft 34 coupled and fixed to the rotation shaft 58 is rotated by an angle equivalent to the rotation amount (rotation angle) of the rotation shaft 58. The valve operating portion 45 is rotated in the valve seat 8 along with the rotation of the valve shaft 34. With this, as illustrated in FIG. 12(a), the one end portion 45 a of the valve operating portion 45 in the circumferential direction gradually opens the first valve port 9. As a result, the lower temperature fluid flowing in from the first housing member 10 through the first inflow port 7 flows into the valve seat 8 through the first valve port 9.

At this moment, as illustrated in FIG. 12(a), the another end portion 45 b of the valve operating portion 45 in the circumferential direction opens the second valve port 18. Accordingly, the higher temperature fluid flowing in from the second housing member 19 through the second inflow port 17 flows into the valve seat 8 through the second valve port 18. Then, the higher temperature fluid mixed with the lower temperature fluid flows out from the third housing member 27 via the valve seat 8 through the outflow port 30 of the valve main body 6. A temperature of the higher temperature fluid is adjusted to a constant temperature (for example, 80° C.), which is higher than a temperature of the lower temperature fluid and is determined in advance.

As illustrated in FIG. 11(b), in the three-way motor valve 1, when the valve shaft 34 is driven to rotate, and the one end portion 45 a of the valve operating portion 45 in the circumferential direction gradually opens the first valve port 9, the lower temperature fluid flowing in through the first housing member 10 and the higher temperature fluid flowing in through the second housing member 19 are mixed in the valve chamber 8 and the valve shaft 34, with the result that the fluid for temperature control is obtained. The fluid for temperature control is supplied to the outside from the third housing member 27 through the outflow port 30 of the valve main body 6.

In the three-way motor valve 1, the valve shaft 34 is rotated as the rotation shaft 58 is driven to rotate. The one end portion 45 a of the valve operating portion 45 in the circumferential direction gradually opens the first valve port 9, and at the same time, the another end portion 45 b of the valve operating portion 45 in the circumferential direction gradually closes the second valve port 18. The lower temperature fluid flowing in through the first valve port 9 and the higher temperature fluid flowing in through the second valve port 18 are mixed in the valve chamber 8 and the valve shaft 34. Then, the resulting fluid for temperature control, which is adjusted in temperature in accordance with a mixture ratio between the lower temperature fluid and the higher temperature fluid, is supplied to the outside through the outflow port 30 of the valve main body 6.

Further, in the three-way motor valve 1, each of the both end portions 45 a and 45 b of the valve operating portion 45 in the circumferential direction has a cross section having a curved-surface shape or a planar shape. Thus, the opening areas of the first and second valve ports 9 and 18 can be linearly changed with respect to the rotation angle of the valve shaft 34. Further, it is conceivable that the lower temperature fluid and the higher temperature fluid regulated in flow rate by the both end portions 45 a and 45 b of the valve operating portion 45 flow in a form of a nearly laminar flow. Therefore, the mixture ratio (flow rate) between the lower temperature fluid and the higher temperature fluid can be controlled with high accuracy in accordance with the opening areas of the first valve port 9 and the second valve port 18.

In the three-way motor valve 1 according to the first embodiment of the present invention, as described above, under an initial state, the valve operating portion 45 of the valve shaft 34 simultaneously closes (completely closes) the first valve port 9 and opens (completely opens) the second valve port 18.

At this time, in the three-way motor valve 1, when the valve operating portion 45 of the valve shaft 34 closes (completely closes) the first valve port 9, ideally, the flow rate of the lower temperature fluid being the first fluid should be zero.

However, as illustrated in FIG. 7, in the three-way motor valve 1, in order to prevent metal-to-metal biting of the valve shaft 34 into the inner peripheral surface of the valve seat 8, the valve shaft 34 is provided in a freely rotatable manner so as to be held in non-contact with the valve seat 8 with a slight gap between the outer peripheral surface of the valve shaft 34 and the inner peripheral surface of the valve seat 8. As a result, the slight gap G2 is defined between the outer peripheral surface of the valve shaft 34 and the inner peripheral surface of the valve seat 8. Accordingly, in the three-way motor valve 1, even when the valve operating portion 45 of the valve shaft 34 closes (completely closes) the first valve port 9, the flow rate of the lower temperature fluid does not become zero, and a small amount of the lower temperature fluid flows to the second valve port 18 side through the slight gap G2 defined between the outer peripheral surface of the valve shaft 34 and the inner peripheral surface of the valve seat 8.

Incidentally, in the three-way motor valve 1 according to the first embodiment of the present invention, as illustrated in FIG. 7, the first valve seat 70 and the second valve seat 80 include the concave portion 74 and the concave portion 84, respectively. The concave portion 74 or the concave portion 84 protrudes from the inner peripheral surface of the valve seat 8 toward the valve shaft 34 side, thereby partially reducing the gap G1 between the outer peripheral surface of the valve shaft 34 and the inner peripheral surface of the valve seat 8.

Therefore, in the three-way motor valve 1, in order to prevent metal-to-metal biting of the valve shaft 34 into the inner peripheral surface of the valve seat 8, even when the valve shaft 34 is provided in a freely rotatable manner so as to be held in non-contact with the valve seat 8 with the slight gap between the outer peripheral surface of the valve shaft 34 and the inner peripheral surface of the valve seat 8, inflow of the lower temperature fluid through the first valve port 9 into the slight gap G2 defined between the outer peripheral surface of the valve shaft 34 and the inner peripheral surface of the valve seat 8 is significantly restricted and suppressed by the gap G1 that is a region corresponding to a partially reduced gap between the outer peripheral surface of the valve shaft 34 and the inner peripheral surface of the valve seat 8.

Accordingly, the three-way motor valve 1 can significantly suppress leakage of the fluid when the three-way motor valve completely closes the valve port as compared to a three-way motor valve that does not include the concave portions 74 and 84 formed to partially reduce the gap between the valve shaft 34 and the first valve seat 70, which is opposed to the valve shaft 34, and the gap between the valve shaft 34 and the second valve seat 80, which is opposed to the valve shaft 34.

Further, similarly, the three-way motor valve 1 can significantly suppress leakage and inflow of the higher temperature fluid, which is the second fluid, through the second valve port 18 to the lower temperature fluid side even when the valve operating portion 45 of the valve shaft 34 closes (completely closes) the second valve port 18.

Experiment Example 1

The inventors of the present invention experimentally produced the three-way motor valves 1 respectively including the valve shafts 34 as illustrated in FIG. 10(a) and FIG. 10(b), and carried out an experiment to check how a flow coefficient Cv value of each of the lower temperature fluid and the higher temperature fluid changes in accordance with opening degrees of the first valve port 9 and the second valve port 18 along with the rotation of the valve shaft 34.

The flow coefficient Cv value of each of the lower temperature fluid, the higher temperature fluid, and the fluid for temperature control, which is a mixture of the lower temperature fluid and the higher temperature fluid, were measured by moving one flow rate sensor having high detection accuracy to each of the first valve port 9, the second valve port 18, and the outflow port 30 individually at the timing when the rotation angle of the valve shaft 34 was changed.

FIG. 13 and FIG. 14 are graphs for showing results of the above-mentioned examples. FIG. 13 corresponds to the valve shaft of FIG. 11(a), and FIG. 14 corresponds to the valve shaft of FIG. 11(b).

As a result, as is apparent from the graphs shown in FIG. 13 and FIG. 14, the flow coefficient Cv value of the lower temperature fluid was substantially linearly increased along with the rotation angle of the valve shaft 34. Simultaneously, the flow coefficient Cv value of the higher temperature fluid was substantially linearly reduced. It has been revealed that the mixture ratio (flow rate) between the lower temperature fluid and the higher temperature fluid can be controlled with high accuracy. Further, as is apparent from the graphs shown in FIG. 13 and FIG. 14, in a region where the opening degree of the valve shaft 34 was 50% or more, the valve shafts of FIG. 11 (a) and FIG. 11(b) each had a region where the flow coefficient Cv value was slightly deviated from the linear line. The reason for this is assumed to be derived from the curved-surface shape of each of the both end portions 45 a and 45 b because, in the case of the valve shaft of FIG. 11 (b), the region where the flow coefficient Cv value was slightly deviated from the linear line was shifted to the region where the opening degree of the valve shaft 34 was higher as compared to the case of the valve shaft of FIG. 11(a).

In the graph shown in FIG. 14, it can be seen that the flow coefficient Cv value of one fluid did not become completely zero even when the valve shaft 34 was rotated to a completely closed position. This is probably because the curvature radius of the outer peripheral side of each of the both end portions 45 a and 45 b of the valve operating portion 45 in the circumferential direction was set larger.

Experiment Example 2

Further, the inventors of the present invention experimentally produced the three-way motor valve 1 including the first valve seat 70 and the second valve seat 80 as illustrated in FIG. 3 and FIG. 4, and carried out an experiment to measure how much the flow rate (leakage amount) of the lower temperature fluid was when the first valve port 9 was completely closed along with rotation of the valve shaft 34. The experiment was carried out under conditions in which the slight gap G1 defined between the outer peripheral surface of the valve shaft 34 and the inner peripheral surface of the valve seat 8 was varied among 150 μm, 28 μm, and 6.5 μm, and a difference in pressure of the lower temperature fluid between an upstream side and a downstream side of the first valve port 9 was varied between 0.44 MPa and 0.68 MPa.

FIG. 15 is a table for showing results of Experiment Example 2.

As is apparent from FIG. 15, in a case in which the gap (clearance) between the outer peripheral surface of the valve shaft and the inner peripheral surface of the valve seat of the valve main body is 150 μm, when the difference in pressure between the first inflow port and the outflow port is 0.44 MPa, a leakage amount per minute is 2.20 L/min. When the difference in pressure between the first inflow port and the outflow port is 0.68 MPa, the leakage amount per minute is significantly increased to 2.73 L/min.

In contrast, in Experiment Example 2, in a case in which the gap (clearance) between the outer peripheral surface of the valve shaft and the inner peripheral surface of the valve seat of the valve main body is set to 28 μm, when the difference in pressure between the first inflow port and the outflow port is 0.44 MPa, the leakage amount per minute is 0.21 L/min. Even when the difference in pressure between the first inflow port and the outflow port is 0.68 MPa, it can be seen that the leakage amount per minute is significantly reduced to 0.26 L/min.

Moreover, in Experiment Example 2, in a case in which the gap (radial clearance) between the outer peripheral surface of the valve shaft and the inner peripheral surface of the valve seat of the valve main body is set to 6.5 μm, when the difference in pressure between the first inflow port and the outflow port is 0.44 MPa, the leakage amount per minute is 0.08 L/min. Even when the difference in pressure between the first inflow port and the outflow port is 0.68 MPa, it can be seen that the leakage amount per minute is further significantly reduced to 0.10 L/min.

Second Embodiment

FIG. 16 is a view for illustrating a three-way motor valve as one example of a flow rate control valve according to a second embodiment of the present invention.

The three-way motor valve 1 according to the second embodiment is structured as the three-way motor valve 1 configured to divide the same fluid into two parts instead of mixing two kinds of different fluids.

The three-way motor valve 1 for division has the same structure as that of the above-mentioned three-way motor valve 1 for mixture. However, as illustrated in FIG. 16, the three-way motor valve 1 for division has an inflow port 26 in a lower end portion of the valve main body 6, and has a first outflow port 7 and a second outflow port 17 in both side surfaces of the valve main body 6, respectively. The other components are the same as those of the above-mentioned three-way motor valve 1 for mixture.

Third Embodiment

FIG. 17 is a view for illustrating a two-way motor valve as one example of a flow rate control valve according to a third embodiment of the present invention.

The two-way motor valve 1 according to the third embodiment is structured as a two-way motor valve 1 for flow rate control, which is configured to control a flow rate of one kind of a fluid.

That is, as illustrated in FIG. 17, the two-way motor valve 1 for flow rate control has the single inflow port 17 in one side surface of the valve main body 6, and has the outflow port 26 in a bottom surface of the valve main body 6. The other components are the same as those of the above-mentioned three-way motor valve 1 for mixture.

Example 1

FIG. 18 is a schematic diagram for illustrating a constant-temperature maintaining device (chiller device) to which the three-way motor valve for flow rate control according to the first embodiment of the present invention is applied.

A chiller device 100 is, for example, used for a semiconductor manufacturing apparatus involving plasma etching, and configured to maintain a temperature of a semiconductor wafer or the like as one example of a temperature control target W to a constant temperature. The temperature control target W, for example, a semiconductor wafer, may rise in temperature along with generation or discharge of plasma or the like after being subjected to plasma etching or the like.

The chiller device 100 includes a temperature control portion 101 constructed to have a table-like shape as one example of the temperature control means arranged so as to be held in contact with the temperature control target W. The temperature control portion 101 has a flow passage 102 for temperature control therein. The fluid for temperature control, which includes the lower temperature fluid and the higher temperature fluid having been adjusted in mixture ratio, flows through the flow passage 102 for temperature control.

The three-way motor valve 1 is connected to the flow passage 102 for temperature control in the temperature control portion 101 through an open/close valve 103. A constant-temperature reservoir 104 for lower temperature is connected to the first flange portion 10 of the three-way motor valve 1. The constant-temperature reservoir 104 for lower temperature stores the low temperature fluid adjusted to a predetermined lower temperature. The lower temperature fluid is supplied to the three-way motor valve 1 from the constant-temperature reservoir 104 for lower temperature by a first pump 105. Further, a constant-temperature reservoir 106 for higher temperature is connected to the second flange portion 19 of the three-way motor valve 1. The constant-temperature reservoir 106 for higher temperature stores the high temperature fluid adjusted to a predetermined higher temperature. The higher temperature fluid is supplied to the three-way motor valve 1 from the constant-temperature reservoir 106 for higher temperature by a second pump 107. The third flange member 27 of the three-way motor valve 1 is connected to the flow passage 102 for temperature control in the temperature control portion 101 through the open/close valve 103.

Further, on an outflow side of the flow passage 102 for temperature control in the temperature control portion 101, a pipe for returning is provided. The pipe for returning is connected to the constant-temperature reservoir 104 for lower temperature and the constant-temperature reservoir 106 for higher temperature.

The three-way motor valve 1 includes a stepping motor 108 configured to drive the valve shaft 34 to rotate. Further, a temperature sensor 109 configured to detect a temperature of the temperature control portion 101 is provided to the temperature control portion 101. The temperature sensor 109 is connected to a control device (not shown), and the control device is configured to control a drive of the stepping motor 108 of the three-way motor valve 1.

As illustrated in FIG. 18, in the chiller device 100, a temperature of the temperature control target W is detected by the temperature sensor 109. Based on a detection result obtained by the temperature sensor 109, the rotation of the stepping motor 108 of the three-way motor valve 1 is controlled by the control device. Accordingly, the temperature control target W is controlled to a temperature equal to a predetermined temperature.

When the valve shaft 34 is driven to rotate by the stepping motor 108, the three-way motor valve 1 controls the mixture ratio between the lower temperature fluid, which is supplied from the constant-temperature reservoir 104 for lower temperature by the first pump 105, and the higher temperature fluid, which is supplied from the constant-temperature reservoir 106 for higher temperature by the second pump 107, to control a temperature of the fluid for temperature control, which is a mixture of the lower temperature fluid and the higher temperature fluid to be supplied to the flow passage 102 for temperature control in the temperature control portion 101 from the three-way motor valve 1 through the open/close valve 103.

At this moment, as illustrated in FIG. 13, the three-way motor valve 1 is capable of controlling the mixture ratio between the lower temperature fluid and the higher temperature fluid in accordance with the rotation angle of the valve shaft 34 with high accuracy, thereby being capable of finely adjusting a temperature of the fluid for temperature control. Thus, the chiller device 100 using the three-way motor valve 1 according to the embodiment of the present invention is capable of controlling a temperature of the temperature control target W, which is held in contact with the temperature control portion 101, to a desired temperature, by allowing the fluid for temperature control, which is controlled in mixture ratio between the lower temperature fluid and the higher temperature fluid and adjusted in temperature to a predetermined temperature, to flow through the flow passage 102 for temperature control in the temperature control portion 101.

Example 2

FIG. 19 is a schematic diagram for illustrating a constant-temperature maintaining device (chiller device) to which the three-way valve for flow rate control according to the second embodiment of the present invention is applied.

The chiller device 100 uses the three-way motor valve 1 in order to divide a fluid for control, which has flowed through the flow passage 102 for temperature control of the temperature control portion 101, between the constant-temperature reservoir 104 for lower temperature and the constant-temperature reservoir 106 for higher temperature. When the valve shaft 34 is driven to rotate by a stepping motor 110, the three-way motor valve 1 controls a flow rate of the fluid for control to be divided between the constant-temperature reservoir 104 for lower temperature and the constant-temperature reservoir 106 for higher temperature.

In a mixing portion 111 in which the lower temperature fluid supplied from the constant-temperature reservoir 104 for lower temperature by the first pump 105, and the higher temperature fluid supplied from the constant-temperature reservoir 106 for higher temperature by the second pump 107 are mixed together, there is used mixing means for mixing the lower temperature fluid and the higher temperature fluid as appropriate after controlling the flow rate of the lower temperature fluid and the flow rate of the higher temperature fluid. As a matter of course, as described above, the three-way motor valve 1 for mixing may be used as the mixing means.

INDUSTRIAL APPLICABILITY

The flow rate control valve is capable of suppressing leakage of a fluid when the flow rate control valve completely closes a valve port. Through use of the flow rate control valve in the temperature control device, a temperature of the temperature control target can be controlled with high accuracy.

REFERENCE SIGNS LIST

-   -   1 . . . three-way motor valve     -   2 . . . valve portion     -   3 . . . actuator     -   4 . . . sealing portion     -   5 . . . coupling portion     -   6 . . . valve main body     -   7 . . . first inflow port     -   8 . . . valve seat     -   9 . . . first valve port     -   10 . . . first flange member     -   11 . . . hexagon socket head cap screw     -   12 . . . flange portion     -   13 . . . insertion portion     -   14 . . . pipe connecting portion     -   15 . . . O-ring     -   16 . . . chamfer     -   17 . . . second inflow port     -   18 . . . second valve port     -   19 . . . second flange member     -   20 . . . hexagon socket head cap screw     -   21 . . . flange portion     -   22 . . . insertion portion     -   23 . . . pipe connecting portion     -   34 . . . valve shaft     -   35 . . . valve body portion     -   45 . . . valve operating portion     -   45 a, 45 b . . . both end portion     -   70, 80 . . . first and second valve seat     -   74, 84 . . . concave portion (gap reducing portion) 

1-8. (canceled)
 9. A flow rate control valve, comprising: a valve main body including a valve seat, the valve seat having a columnar space and having one or a plurality of valve ports, which allow a fluid to flow therethrough and each have a rectangular cross section; a valve body being provided in a freely rotatable manner in the valve seat of the valve main body so as to open and close the one or the plurality of valve ports, the valve body having a cylindrical shape and having an opening formed in an outer peripheral surface of the valve body; a gap reducing portion being provided so as to partially reduce a gap between the valve body and a member opposed to the valve body; and drive means for driving the valve body to rotate, wherein the one or the plurality of valve ports are each formed by a valve port forming member, which is a member provided separately from the valve main body, and wherein the gap reducing portion is formed of a distal end portion of the valve port forming member opposed to the valve body.
 10. A flow rate control valve, comprising: a valve main body including a valve seat, the valve seat having a columnar space and having a first valve port, which allows inflow of a first fluid and has a rectangular cross section, and a second valve port, which allows inflow of a second fluid and has a rectangular cross section; a valve body being provided in a freely rotatable manner in the valve seat of the valve main body so as to simultaneously switch the first valve port from a closed state to an opened state and switch the second valve port from an opened state to a closed state, the valve body having a half-cylindrical shape with a predetermined central angle and having a curved-surface shape or a flat-surface shape at each of both end surfaces of the valve body in a circumferential direction; a gap reducing portion being provided so as to partially reduce a gap between the valve body and a member opposed to the valve body; and drive means for driving the valve body to rotate, wherein the one or the plurality of valve ports are each formed by a valve port forming member, which is a member provided separately from the valve main body, and wherein the gap reducing portion is formed of a distal end portion of the valve port forming member opposed to the valve body.
 11. A flow rate control valve, comprising: a valve main body including a valve seat, the valve seat having a columnar space and having a first valve port, which allows outflow of a fluid and has a rectangular cross section, and a second valve port, which allows outflow of the fluid and has a rectangular cross section; a valve body being provided in a freely rotatable manner in the valve seat of the valve main body so as to simultaneously switch the first valve port from a closed state to an opened state and switch the second valve port from an opened state to a closed state, the valve body having a half-cylindrical shape with a predetermined central angle and having a curved-surface shape or a flat-surface shape at each of both end surfaces of the valve body in a circumferential direction; a gap reducing portion being provided so as to partially reduce a gap between the valve body and a member opposed to the valve body; and drive means for driving the valve body to rotate, wherein the one or the plurality of valve ports are each formed by a valve port forming member, which is a member provided separately from the valve main body, and wherein the gap reducing portion is formed of a distal end portion of the valve port forming member opposed to the valve body.
 12. A flow rate control valve, comprising: a valve main body including a valve seat having a columnar space, the valve main body having a first valve port, which allows a fluid to flow therethrough and has a rectangular cross section, and a third valve port, which allows the fluid to flow therethrough, the first valve port being formed in a peripheral surface of the valve seat, the third valve port being formed in one end portion of the valve seat in an axial direction; a valve body being provided in a freely rotatable manner in the valve seat of the valve main body, the valve body having a shape corresponding to part of a cylindrical shape with a predetermined central angle, so as to linearly change an opening area of the first valve port; a gap reducing portion being provided so as to partially reduce a gap between the valve body and a member opposed to the valve body; and drive means for driving the valve body to rotate, wherein the one or the plurality of valve ports are each formed by a valve port forming member, which is a member provided separately from the valve main body, and wherein the gap reducing portion is formed of a distal end portion of the valve port forming member opposed to the valve body.
 13. The flow rate control valve according to any one of claims 9 to 12, further comprising a gap adjusting member configured to adjust a gap between the valve body and the gap reducing portion.
 14. A temperature control device, comprising: temperature control means having a flow passage for temperature control, which allows a fluid for temperature control to flow therethrough, the fluid for temperature control including a lower temperature fluid and a higher temperature fluid adjusted in mixture ratio; first supply means for supplying the lower temperature fluid adjusted to a first predetermined lower temperature; second supply means for supplying the higher temperature fluid adjusted to a second predetermined higher temperature; and a flow rate control valve connected to the first supply means and the second supply means, and configured to adjust the mixture ratio between the lower temperature fluid supplied from the first supply means and the higher temperature fluid supplied from the second supply means and allow the fluid for temperature control to flow through the flow passage for temperature control, wherein the flow rate control valve of claim 9 or 10 is used as the flow rate control valve.
 15. A temperature control device, comprising: temperature control means having a flow passage for temperature control, which allows a fluid for temperature control to flow therethrough, the fluid for temperature control including a lower temperature fluid and a higher temperature fluid adjusted in mixture ratio; first supply means for supplying the lower temperature fluid adjusted to a first predetermined lower temperature; second supply means for supplying the higher temperature fluid adjusted to a second predetermined higher temperature; mixing means, which is connected to the first supply means and the second supply means, for mixing the lower temperature fluid supplied from the first supply means and the higher temperature fluid supplied from the second supply means and supplying a mixture of the lower temperature fluid and the higher temperature fluid to the flow passage for temperature control; and a flow rate control valve configured to divide the fluid for temperature control having flowed through the flow passage for temperature control between the first supply means and the second supply means while controlling a flow rate of the fluid for temperature control, wherein the flow rate control valve of claim 9 or 11 is used as the flow rate control valve. 